a. Field of the Invention
The invention relates to one of the steps in the pulping of cellulosic materials to make paper and more particularly to a drum washer for washing of the pulp to remove pulping liquors and the filtrate liquid sampling system of such drum washer to provide a continuous correlatable measurement of the solids content in the mat discharged from the drum washer.
b. Description of the Prior Art
The prior art includes measurement of drop leg conductivity. Since most of this filtrate is recycled back to the washer vat and includes all filtrate drawn through the drum, it is considered an insensitive measure of discharge mat solids concentration and therefore inadequate for feedback control purposes. In addition there are mat sampling techniques, but these are manual and therefore not applicable to feedback control.
The sampling system of the present invention provides a continuous fed flow of filtrate from the atmospheric port of the vacuum shoe of the drum washer. This drainage from the final displacement zone of the drum can be continuously analyzed for solids content which is a direct indication of the washing efficiency. This is useful for feedback control and optimization of the drum washer.
Such system has not been found in the prior art.